CHLAMYDIA ANTIBODY TITRE AS A PREDICTOR OF TUBAL FACTOR INFERTILITY

BACKGROUND: Genital Chlamydia trachomatis is major cause of tubal factor infertility. Assessment of tubal patency by hysterosalpingography (HSG) and laparoscopy are invasive and expensive. In low resource setting, there may be a place for Chlamydia Antibody Titre (CAT) in infertility work up. Objective: To determine the predictive value of Chlamydia antibody titre in tubal factor infertility. Materials and Methods: This was a prospective cross-sectional study of women presenting with infertility at the Human Reproduction Research Programme unit of the University of Benin

Infertility is a significant public health problem in our environment where a high premium is placed on the ability to bear children.Its prevalence has been estimated to 1 be 6.9 -9.3% in developing countries .Tubal damage is a major cause of infertility 2 with a reported incidence of 13.5% to 38% .At the University of Benin Teaching Hospital, it was responsible as the sole cause of tubal disease, requires general anaesthesia, hence it is not a suitable method for screening for tubal disease on a large scale.More so, it is not readily available in l o w r e s o u r c e s e t t i n g l i k e o u r s .Hysterosalpingogram is the most widely used screening test for tubal factor infertility.The overall sensitivity of HSG for the detection of tubal damage is only 65% with a specificity of 17 83% .HSG is a painful procedure, has risk of infection, ionizing radiation and is poor at

MATERIALS AND METHODS
This was a prospective cross-sectional study of women who presented for infertility treatment at the Human Reproduction Research Programme (HRRP) unit of the department of Obstetrics and Gynaecology, University of Benin Teaching Hospital.Exclusion Criteria included women with previous pelvic or abdominal surgery, and w o m e n w i t h c o n t r a i n d i c a t i o n s t o laparoscopy.Approval for this study was obtained from the ethical committee of the hospital.All participants gave written informed consent.A woman was considered to have tubal factor infertility if she had bilateral tubal occlusion on HSG or at laparoscopy.Socio-economic class was as described by 19 Olusanya et al .Upon recruitment, data was obtained using pretested data retrieval form after clients were assured of confidentiality.Data extracted included socio-demographic characteristics (age, parity, level of education, occupation, ethnic group, social class), type of infertility (primary or secondary), duration of infertility, previous history of PID.Thereafter each woman had serological assay for Chlamydia antibody as well as hysterosalpingography done while laparoscopy was done when indicated.For Chlamydia antibody assay, 5ml of venous blood was collected from the volar surface of the forearms of all patients into clear sterile plain bottle.The blood specimen was allowed to clot, and then centrifuged to obtain serum.The serological assay was done using the immunocomb Chlamydia trachomatis immunoglobulin G kit (orgenics, Isreal), an indirect solid phase enzyme immunoassay (EIA) test that quantitatively measures antibodies to Chlamydia trachomatis in human serum.This was statistically significant (P = 0.037).
There was no significant difference in the social class of patient with positive and negative Chlamydia antibody titre (P = 0.16).
There was also no significant difference in the parity distribution between those with positive CAT and negative CAT.Table II compared the clinical characteristics of women with positive and negative CAT.The type of infertility (primary or secondary) was not different among patients with positive or negative CAT.The duration of infertility was significantly longer among women with positive CAT (6.3 4.11 vs 5.19 3.23 years, p = 0.046).Only 10% of women reported a history of previous pelvic inflammatory diseases and there was no significant difference between the two groups.Women with positive CAT were significantly more likely to have tubal occlusion on HSG than women with negative CAT (72.1% vs 17.1%; p = 0.000).Table 3 shows the comparison of the CAT and HSG with laparoscopy findings among the 19 patients that had laparoscopy.There was a significant association between positive CAT and abnormal laparoscopy as against positive CAT and normal laparoscopy (84.6% vs 33.3%, p = 0.046).There was no significant association between tubal occlusion on HSG and abnormal laparoscopy.(92.3% vs 50%, p = 0.071).Table 4 shows the comparison of CAT and HSG using sensitivity, specificity, positive and negative likelihood ratios.The sensitivity of a positive CAT was 84.6% with specificity of 66.7% at detecting tubal disease.
The LR+ of CAT was 2.58, indicating that a patient with tubal factor infertility is 2.58 times more likely to have a positive test result (i.e.titre > 32).HSG had a sensitivity of 85.7% and a specificity of 50% at detecting tubal disease.The LR+ of HSG was 1.72.The LR -of CAT was 0.22, indicating a patient with tubal factor infertility to be 0.22 times as likely to have a negative CAT (i.e.< 32) compared to a patient without the disease.The LR -of HSG was 0.28.

DISCUSSION
Tubal damage due to Chlamydia trachomatis 6,9 infection is an important cause of infertility .This study reports a prevalence of 32.1% of positive Chlamydia antibody titre among infertile patients.This is lower than the 65.8%  hysterosalpingogram and laparoscopy.This may have accounted for the high prevalence in their study.Our study included all women with infertility irrespective of the aetiology and further analysis revealed that the prevalence of Chlamydia antibody titre among women with tubal occlusion on HSG is 72.1% showing that the prevalence of positive CAT was higher among women with tubal damage.The differences may also be due to differences in diagnostic test for Chlamydia.Logan  prevalence reported from their studies.Results from this study show that CAT and HSG have comparable sensitivity (84.6% vs 85.7%).The clinical implication of this is that both will have similar false negative rates.However, HSG is less specific at detecting tubal disease (66.7% vs 50%) and will have a higher false positive rate compared to CAT.The sensitivity and specificity of CAT found in this study is comparable to that reported by decline in titers .This may suggest that older patients will have less positive rate than younger patients.This is however at variance with the findings from this study which showed that older patients are more likely to have positive CAT than younger patients.A more recent study has also revealed no significant decline in Chlamydia antibody 28 titre with age .Another explanation for false negative results is the immune-mediated reaction responsible for adhesion; or, for unknown reasons, tubal occlusion may not 29 have occurred in these women .Therefore false negative test results may lead to expectant management.However, the strength of using this study is the fact that the decision to perform a diagnostic laparoscopy was irrespective of the result of CAT.

CONCLUSION AND RECOMMENDATIONS
This study shows evidence that CAT test is useful in selecting patients that are more likely to benefit from early recourse to the use of HSG or laparoscopy to exclude or rule in tubal factor infertility.We however recommend a larger population study to validate these findings.

3 infertilityconsequences for female reproductive health 7 .
in 14% of patients .The damage is most commonly due to ascending genital tract 4 infection and the two organisms frequently implicated are Neisseria gonorrhoea and Chlamydia trachomatis.It has been shown that most cases are caused by Chlamydia 5 t r a c h o m a t i s .G e n i t a l C h l a m y d i a t r a c h o m a t i s i n f e c t i o n s a r e o f t e n asymptomatic with potential long term 6-Among infertile women, evidence of previous INTRODUCTION a Department of Obstetrics and Gynaecology, University of Benin Teaching Hospital, Benin City, Edo State, Nigeria tubal damage than other agents despite its 11 more benign presentation .Superficial infection is considered to provide a weak stimulus for antibody formation, whereas infiltrating disease leading to upper genital 12 infection is associated with sero-conversion .Immunoglobulin M (IgM) production is often transient, whereas serum IgG antibodies persist for years and can be used as a marker 4 of previous infiltrating Chlamydia infection .A number of studies have investigated the antibody responses produced by Chlamydia trachomatis and have generally found a good correlation between serum antibodies to Chlamydia trachomatis and pelvic inflammatory disease and tubal factor 6,12,13 infertility .Mol et al demonstrated a positive correlation between Chlamydia 14 antibody titre and tubal factor infertility .Tuboperitoneal disease can be diagnosed by h y s t e r o s a l p i n g o g r a p h y ( H S G ) o r laparoscopy.These are both invasive and expensive procedures.Laparoscopy, though still the gold standard for the diagnosis of 4 , 1 2 , 1 5 , 1 6

16 al.
The observed difference in prevalence rate may be due to the difference in population studied.The study by Omo-Aghoja et al used women with proven tubal f a c t o r i n f e r t i l i t y c o n f i r m e d b y et al used enzyme immunoassay and subsequently nucleic acid amplification assay.All positive EIA test w e r e c o n f i r m e d b y d i r e c t immunoflourescence and all positive samples were further retested.These series of tests as well as the use of nuclieic acid amplification 22-24 test with specificity approaching 100% may have been responsible for the low Chlamydia Antibody Titre as A Predictor of Tubal Factor Infertility Ibom Medical Journal Vol.11 No.2 August, 2018

AZIKEN MBBS,MPH,FWACS,FMCOG,FICS,DMAS ; Ibom Medical Journal Vol.11 No.2 August, 2018 brought
to room temperature and then about 3.5ml pipette serum analysed with reagent control samples for Chlamydia trachomatis IgG antibodies.The results were recorded with the aid of calorimetric calibration scale in titres.The tests were validated with the control samples and significant titre (positive The reagent test kit was a a Oghenefegor E. OLOKOR ;MBBS,FWACS, Michael E.